Folic acid (Folate)
Keywords: protein and DNA synthesis, amino acid metabolism, mental health, homocysteine, preventing birth defects, easily destroyed by heat
- Blood formation
- Melanin synthesis
- Metabolism of methionine, phenylalanine, tyrosine
- Protein, RNA and DNA synthesis
- Synthesis of purines and pyrimidines
- Synthesis of the amino acids glycine and methionine
Good food sources
- Leafy green vegetables, especially raw spinach
- Freshly squeezed orange juice
- Soy flour
- Whole grains
- Yeast extract
Deficiency signs and symptoms
- Birth defects in children
- Constipation and digestive disturbances
- Growth impairment
- Habitual miscarriage
- Increased risk of cancer
- Increased risk of heart disease (by causing raised homocysteine levels)
- Memory impairment
- Mental confusion
- Paranoid delusions
- Reduced immunity
- Sore tongue
Low levels of several B vitamins have been found in psychiatric patients and in senile dementia.
Folic acid is one of the vitamins most easily destroyed by heat, therefore vegetables should be cooked for as short a time as possible. Whole-grain foods should be eaten instead of white flour products and white rice. The cumulative losses of folic acid from food processing can amount to 65 per cent, leaving many foods with only one third of their original folic acid content. Prolonged boiling can cause losses of up to 50 per cent. Like vitamin B2, folic acid is sensitive to light. The bioavailability of folic acid is reduced by alcohol consumption, the contraceptive pill, aspirin, cimetidine (Zantac), antacids, zinc deficiency, vitamin B12 deficiency, and the ageing process. Folic acid deficiency is relatively common in malnourished hospitalized patients. Certain tissues can be more folate-deficient than others: for instance precancerous changes can occur in the cervix, lung or colon which are reversible with folic acid supplementation (Heimburger DC: Localized deficiencies of folic acid in aerodigestive tissues. Ann NY Acad Sci 1992669:87-95).
Vitamin B12 deficiency causes folate deficiency by causing folic acid to be trapped as methylfolate, which is unavailable to the body. A deficiency of the amino acid methionine has a similar effect. Oral contraceptives or deficiencies of vitamins B3 or C also prevent adequate utilization.
Folic acid itself does not occur in food or human tissue unless taken as a dietary supplement, and it is physiologically inactive until it has been reduced to dihydrofolic acid. Folic acid is in fact the parent molecule for a number of derivatives known collectively as folates.
Information compiled by Linda Lazarides
Naturopathic Nutritionist, Author, Educator